There exist several search engines, for example Yahoo!®, or other mechanisms to search results on internet and to provide the results to a user. The search engines depend on one or more probabilistic models, or algorithms to provide the results to the user in response to a query inputted by the user. Query reformulation or query rewriting is a technique that is often used by search engines for identifying the results that are relevant to the query. The query reformulation includes determining similarity scores among various queries to identify several queries that are logically similar to the query inputted by the user. The results are then identified based on determined queries. However, the query reformulation is a challenge in itself. Moreover, it is desired to perform query reformulation accurately and efficiently in presence of increasing queries or contents such as user history.